1. Field of the Invention
The present invention relates to imidazopyridine-based compounds and to organic light emitting diodes including organic layers comprising the imidazopyridine-based compounds. More particularly, the invention is directed to imidazopyridine-based compounds suitable for electron transport layers of organic light emitting diodes and to organic light emitting diodes including organic layers comprising the imidazopyridine-based compounds.
2. Description of the Related Art
Organic Light emitting diodes (OLEDs) are self-emitting diodes having wide viewing angles, excellent contrast, and quick response times.
Further, organic light emitting diodes have good luminance, operating voltage and response times, and can realize multicolor images.
In a conventional organic light emitting diode, an anode is formed on a substrate, and a hole transport layer, an emissive layer, an electron transport layer and a cathode are sequentially formed on the anode. The hole transport layer, the emissive layer and the electron transport layer are organic thin films formed of organic compounds. An organic light emitting diode having such a structure operates as follows. When a voltage is applied to the anode and cathode, holes injected from the anode migrate to the emissive layer via the hole transport layer. The electrons injected from the cathode migrate to the emissive layer via the electron transport layer. The holes and the electrons recombine with each other in the emissive layer to generate excitons. When the excitons drop from an excited state to a ground state, fluorescent molecules of the emissive layer emit light. Heteroaromatic compounds such as oxidiazoles, thiadiazoles, pyrimidines and the like may be used as the material for forming the electron transport layer. However, conventional organic light emitting diodes do not have satisfactory driving voltages, luminance, current densities, power efficiencies, life-times and the like.